class EntityViewHookTest

class EntityViewHookTest extends EntityKernelTestBase {
    
    /**
     * Tests hook_entity_display_build_alter().
     */
    public function testHookEntityDisplayBuildAlter() {
        entity_test_create_bundle('display_build_alter_bundle');
        
        /** @var \Drupal\Core\Render\RendererInterface $renderer */
        $renderer = $this->container
            ->get('renderer');
        $entity_ids = [];
        // Create some entities to test.
        for ($i = 0; $i < 5; $i++) {
            $entity = EntityTest::create([
                'name' => $this->randomMachineName(),
                'type' => 'display_build_alter_bundle',
            ]);
            $entity->save();
            $entity_ids[] = $entity->id();
        }
        
        /** @var \Drupal\entity_test\EntityTestViewBuilder $view_builder */
        $view_builder = $this->container
            ->get('entity_type.manager')
            ->getViewBuilder('entity_test');
        
        /** @var \Drupal\Core\Entity\EntityStorageInterface $storage */
        $storage = $this->container
            ->get('entity_type.manager')
            ->getStorage('entity_test');
        $storage->resetCache();
        $entities = $storage->loadMultiple($entity_ids);
        $build = $view_builder->viewMultiple($entities);
        $output = $renderer->renderRoot($build);
        $this->setRawContent($output->__toString());
        // Confirm that the content added in
        // entity_test_entity_display_build_alter() appears multiple times, not
        // just for the final entity.
        foreach ($entity_ids as $id) {
            $this->assertText('Content added in hook_entity_display_build_alter for entity id ' . $id);
        }
    }

}